Which assay is used to quantify PSA in serum?

Which assay is used to quantify PSA in serum?

• A. Immunoassay
• B. Gel electrophoresis
• C. Mass spectrometry
• D. Western blot

Answer: (A)

PSA in serum is quantified most reliably with an antibody-based immunoassay. This approach uses antibodies that specifically recognize PSA to capture the protein from the blood and then a second antibody with a detectable label binds to PSA to produce a signal that is proportional to the amount present. The result is highly specific, sensitive, and can be automated for high-throughput clinical testing, providing accurate quantification across the relevant PSA range. Gel electrophoresis separates proteins by size and isn’t suitable for routine, quantitative measurement of PSA in a complex serum sample. Mass spectrometry can quantify PSA but is more complex, time-consuming, and costly for routine screening, making it less practical for standard clinical use. Western blot identifies or confirms the presence of proteins but is not ideal for routine, quantitative serum PSA testing.

PSA in serum is quantified most reliably with an antibody-based immunoassay. This approach uses antibodies that specifically recognize PSA to capture the protein from the blood and then a second antibody with a detectable label binds to PSA to produce a signal that is proportional to the amount present. The result is highly specific, sensitive, and can be automated for high-throughput clinical testing, providing accurate quantification across the relevant PSA range.

Gel electrophoresis separates proteins by size and isn’t suitable for routine, quantitative measurement of PSA in a complex serum sample. Mass spectrometry can quantify PSA but is more complex, time-consuming, and costly for routine screening, making it less practical for standard clinical use. Western blot identifies or confirms the presence of proteins but is not ideal for routine, quantitative serum PSA testing.